ISL1539A_14 Datasheet, PDF (1/23 Pages) Intersil Corporation – Dual Port VDSL2 Line Driver

Dual Port VDSL2 Line Driver
ISL1539A
The ISL1539A provides 4 internal wideband op amps
intended to be used as two pairs of differential line
drivers. The ISL1539A’s high bandwidth, 240MHz, and
ultra low distortion, -89dBc @ 1MHz, 2V_P-P, support the
demanding MTPR requirements of emerging VDSL2 line
driver designs. Less demanding requirements can be met
at very low quiescent powers using the supply current
adjustment features.
Each of the 4 internal op amps is a wideband current
feedback amplifier offering very high slew rate intrinsic to
that design using low quiescent current levels. Each of
the two pair of amplifiers (ports) can also be power
optimized to the application using two external quiescent
control logic pins. Full power is nominally 27.2mA/port
with options of medium power cutback to 23mA/port, a
low power condition at 13.5mA/port, and an off state at
<0.5mA/port. Added quiescent power flexibility is
provided through an external I_ADJ pin. Grounding the pin
gives the nominal currents listed above while inserting a
resistor from this pin to ground can be used to scale each
of the settings downward.
High power push/pull line driver applications as
illustrated in the example below are best supported using
a low headroom, high output current device. On ±12V
supplies, the ISL1539A offers a 1.1V headroom with
>360mA peak output current. Driving differentially this
gives >41.8V_P-P swing to as low as 58Ω differential load.
High SFDR operation is also supported for supplies as low
as ±7.5V. Intended to be used as differential pairs, this
two port device includes special circuitry to minimize
common mode loop peaking while also reducing the
common mode output noise spectrum. That circuitry
links the two sides of each port, precluding their
application as individual amplifiers.
Features
• 360mA Output Drive Capability
• 41.8V_P-P Differential Output Drive into 100Ω
• -89dBc THD @ 1MHz 2V_P-P
• -65dBc MTPR (VDSL 8b Profile)
• High Slew Rate of 3000V/µs Differential
• Bandwidth (240MHz @ A_V-DIFF = 10)
• Supply Current Control Pins
• Port Separation
- 78dB @ 500kHz
- 70dB @ 1MHz
- 60dB @ 4MHz
• Pb-Free (RoHS Compliant)
Applications*(see page 21)
• 8MHz and 17MHz VDSL2 Profiles
• ADSL2+
Related Literature (see Device Info page)
• AN1325 “Choosing and Using Bypass Capacitors”
• TB426 “Characterization of the Output Protection
Circuitry of the EL1528 DSL Driver for Lightning
Surges”
TABLE 1. ALTERNATE SOLUTIONS
NOMINAL ±V_CC BANDWIDTH
PART #
(V)
(MHz) APPLICATIONS
ISL1557
±6
200
VDSL
ISL1534
±12
40
ADSL2+
ISL1536
±12
50
ADSL2+
Typical Application
+12V
Rb ^{+ ¼}
Ro
ISL1539A
- Rf
3.2kΩ
1:n
VI
SOURCE
Rg 711^Ω
VO
LOAD
Rf
- ^3.2kΩ
¼
ISL1539A
Ro
+
Rb
AV-DIFF = VO/VI = 10V/V
-12V
TYPICAL DIFFERENTIAL I/O LINE DRIVER
(1 OF 2 PORTS)
4MHz Harmonic Distortion
V_S = ±12V
AV = +10
R_F = 3.2kΩ
R_L = 100Ω DIFF
3rd HD
2nd HD
THD
September 23, 2009
FN6916.0
1
CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures.
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